Microelectrode recordings from transected nerves in amputees with phantom limb pain

Intraneural microelectrode recordings were made from the nerve supplying the phantom area in two patients suffering from phantom limb pain. Spontaneous activity was prominent in both cutaneous and muscle fascicle of the nerves. Tapping the neuromata which accentuated the phantom limb pain, induced afferent discharges with both short and long latencies, the latter from fibres with a conduction velocity of only 0.5 m/sec. Blocking the neuromata with lidocaine completely abolished the tap-induced afferent discharges and the tap-induced accentuation of the phantom pain. The spontaneous pain was, however, unchanged, as was the spontaneous activity recorded.     

The cortical somatotopic map and phantom phenomena in subjects with congenital limb atrophy and traumatic amputees with phantom limb pain

The extent of the cortical somatotopic map and its relationship to phantom phenomena was tested in five subjects with congenital absence of an upper limb, four traumatic amputees with phantom limb pain and five healthy controls. Cortical maps of the first and fifth digit of the intact hand, the lower lip and the first toe (bilaterally) were obtained using neuroelectric source imaging. The subjects with congenital upper limb atrophy showed symmetric positions of the left and right side of the lower lip and the first toe, whereas the traumatic amputees with pain showed a significant shift (about 2.4 cm) of the cortical representation of the lower lip towards the hand region contralateral to the amputation side but no shift for the toe representation. In healthy controls, no significant hemispheric differences between the cortical representation of the digits, lower lip or first toe were found. Phantom phenomena were absent in the congenital but extensive in the traumatic amputees. These data confirm the assumption that congenital absence of a limb does not lead to cortical reorganization or phantom limbs whereas traumatic amputations that are accompanied by phantom limb pain show shifts of the cortical areas adjacent to the amputation zone towards the representation of the deafferented body part.     

A prospective analysis of acceptance of pain and values-based action in patients with chronic pain.

Objective: Acceptance of pain and values-based action appear important in the emotional, physical, and social functioning of individuals with chronic pain. The purpose of the current study was to prospectively investigate these combined processes. Method: 115 patients attending an assessment and treatment course for chronic pain in the U.K. completed a standard set of measures on two occasions separated by an average of 18.5 weeks. Results: Correlation analyses showed that acceptance of pain and values-based action measured at Time 1 were significantly correlated with pain, pain-related distress, pain-related anxiety and avoidance, depression, depression-related interference with functioning, and physical and psychosocial disability measured at Time 2. Multiple regression analyses, in which pain and relevant patient background variables were controlled, showed that the combined acceptance and values measures accounted for between 6.5% and 27.0% of variance in six key measures of patient functioning later in time. Conclusion: These results support the importance of acceptance and values-related processes in relation to chronic pain. These results also encourage continued applications of a functional contextual model of psychopathology, the model underlying Acceptance and Commitment Therapy and related approaches such as Contextual Cognitive-Behavioral Therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Incidence of chronic pain following traumatic brain injury

OBJECTIVE: To index the frequency of reported chronic pain in patients with traumatic brain injury (TBI). DESIGN: A case series study was conducted on consecutive patients with TBI. SETTING: TBI patients were recruited from an adult tertiary care center brain injury clinic. PATIENTS: A consecutive sample of 132 patients who attended a brain injury rehabilitation center after TBI. The sample included 53 mild and 79 moderate/severe TBI patients. OUTCOME MEASURES: Patients were administered a protocol that indexed pain site, frequency, severity, and duration. RESULTS: Chronic pain was reported by 58% of mild TBI and 52% of moderate/severe TBI patients. Headaches were the most commonly reported pain problem. Chronic headaches were reported by 47% of mild TBI patients and 34% of moderate/ severe TBI patients. Neck/shoulder, back, upper limb, and lower limb pain were reported similarly by mild and moderate/severe TBI patients. CONCLUSIONS: Findings indicate that chronic pain is a significant problem in mild and moderate/severe TBI patients. More effective diagnosis of TBI patients with chronic pain may facilitate rehabilitation of these patients.     

Does pain interference mediate the relationship of independence in ambulation with depressive symptoms after spinal cord injury?

Purpose/Objective: To test a mediational model that hypothesizes pain interference mediates the relationship between ambulatory status and depressive symptoms among participants with traumatic spinal cord injury (SCI). Research Method/Design: Responses to the Brief Pain Index (pain interference) and the Older Adult Health and Mood Questionnaire (depressive symptoms) were obtained from 1,545 adults with SCI. Logistic regression was used to calculate the odds of clinically significant symptomatology and probable major depression as a function of independence in ambulation and to evaluate the extent to which pain interference mediated the relationship between ambulation and a depressive diagnosis. Results: Partially dependent ambulators reported significantly greater odds of clinically significant symptomatology (2.30) and probable major depression (2.00) compared with independent ambulators prior to evaluation of pain interference (comparisons of wheelchair users with independent ambulators were not significant). However, these relationships were no longer significant after controlling for pain interference. Conclusions/Implications: Pain interference appears to mediate the relationship between ambulatory status and depressive symptoms after SCI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of traumatic onset, compensation status, and physical findings: impact on pain severity, emotional distress, and disability in chronic pain patients

The primary purposes of the present study were to investigate the roles of physical findings, financial compensation, and types of pain onset (i.e., trauma vs. insidious onset) on adaptation by chronic pain patients. Comparisons between patients who were receiving or seeking compensation and those who were not revealed that, despite comparable degrees of physical findings, the compensation status was associated with reports of (a) more severe pain, (b) greater disability, (c) higher levels of emotional distress, and (d) greater life interference. The compensation status of 74% of the patients was correctly classified by combination of pain severity, perceived disability, and life interference. Objective indices of physical findings did not significantly improve classification accuracy. In order to eliminate the possible confound of compensation, analyses of the relationship between the types of onset and chronic pain were conducted only for a subset of patients who were not receiving or actively seeking compensation. The results indicated that the patients who attributed their pain to a specific trauma reported significantly higher levels of emotional distress, life interference, and higher levels of pain severity than did the patients who indicated that their pain had an insidious or spontaneous onset, regardless of the extent of objective physical findings.     

Catastrophizing mediates associations between pain severity, psychological distress, and functional disability among persons with spinal cord injury.

Objective: To examine associations between pain severity, psychological distress, catastrophizing, and indices of functional disability in a sample of persons with spinal cord injury (SCI). Catastrophizing was examined as a potential mediator of associations between pain severity, psychological distress, and functional disability. Design and Participants: Questionnaires assessing pain severity, psychological distress, catastrophizing, pain interference, and community integration were completed by 237 persons with SCI. Results: Psychological distress and pain severity were associated significantly with greater functional disability. Moreover, the association between pain severity and functional disability was strongest among persons with high psychological distress. Catastrophizing appeared to mediate the associations between pain severity, psychological distress, and functional disability. Conclusions: Pain severity and psychological distress have the potential for both direct and interactive effects on functional disability, possibly through the mediating effects of catastrophizing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pain in young adults: I. Relationship to gender and family pain history

OBJECTIVES/DESIGN: Two studies were carried out to examine how gender and family pain history related to pain and activity interference in young adults. The first study (n = 252 college students) examined how gender and family pain history related to pain intensity and the second study (n = 206 college students) examined how these variables related to pain intensity, location, and activity interference. Whenever possible, data from the two studies were combined for purposes of data analyses. RESULTS: Results indicated that more than half of the young adults studied reported experiencing some type of pain at the time of the investigation. The intensity of the pain was in the low range and the most frequent sites of pain were in the head and legs or feet. Gender differences were noted, with women reporting a greater number of sites of pain. Family pain history was found to be related to pain and activity interference. Subjects who had a strong family history of pain problems reported a greater number of pain sites, and higher levels of pain-related activity interference. CONCLUSIONS: Generalizability of results is limited due to the group of young adults studied, yet several conclusions relative to this group may be suggested. First, this group of young adults do appear to experience pain. Second, there may be gender differences in the types of pain they report and the ways they react to pain. Third, family history of pain may be related to the pain experiences of this group of young adults.     

An examination of the co-morbidity between chronic pain and posttraumatic stress disorder on U.S. Veterans.

The purpose of this study was to assess the comorbidity between chronic pain and posttraumatic stress disorder (PTSD) and examine the extent to which PTSD is associated with changes in the multidimensional experience of pain in a sample of Veterans with chronic pain. It was hypothesized that Veterans with comorbid chronic pain and PTSD would report significantly higher scores on measures of pain intensity, pain behaviors, pain-related disability, and affective distress than Veterans with pain alone. Data were obtained from 149 Veterans who completed self-report questionnaires as part of their participation in a Psychology Pain Management program at a northeastern Department of Veterans Affairs health care facility. Analyses indicated that 49% of the sample met criteria for PTSD. A multivariate analysis of covariance was conducted with age, sex, pain duration, and depressive symptom severity as covariates. In partial support of our hypothesis, the presence of PTSD was found to contribute significantly to measures of affective distress, even after controlling for the effects of depressive symptom severity. The implications of these data are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of the efficacy of electromyographic biofeedback, cognitive-behavioral therapy, and conservative medical interventions in the treatment of chronic musculoskeletal pain.

Compared 3 types of treatments for chronic musculoskeletal pain. 57 patients who suffered from chronic back pain and 21 patients who suffered from temporomandibular pain and dysfunction were randomly assigned to either electromyographic (EMG) biofeedback, cognitive-behavioral therapy, or conservative medical treatment. At posttreatment, improvements were noted in all 3 treatment groups, with the biofeedback group displaying the most substantial change. At the 6- and 24-mo follow-up, only the biofeedback group maintained significant reductions in pain severity, interference, affective distress, pain-related use of the health care system, stress-related reactivity of the affected muscles, and an increase in active coping self-statements. Treatment outcome was predicted by chronicity and treatment-specific variables. Analysis of attrition showed a significant effect for therapist and extent of somatic pathology. Results suggest that pain patients who suffer from musculoskeletal pain problems and display few physical disabilities may profit the most from short-term EMG biofeedback treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Catastrophizing, acceptance, and interference: Laboratory findings, subjective report, and pain willingness as a moderator.

Objective: The present study investigated the effects of both catastrophizing and the pain willingness component of acceptance on interference in daily activities and task performance during experimentally induced ischemic pain. In addition, the potential moderating role of pain willingness on the relationship between catastrophizing and degree of pain interference was also examined. Design: Sixty-seven persons with chronic low back pain completed measures of catastrophizing, acceptance, and daily pain interference. Participants underwent an ischemic pain induction procedure during which a Stroop-like task was administered. Main Outcome Measures: Self-reported pain interference and observed performance on a Stroop-like task during induced pain. Results: The pain willingness component of acceptance and catastrophizing both contributed significantly to self-reports of pain interference. However, levels of pain willingness had an effect much stronger than the negative effects associated with catastrophizing with respect to observed pain interference during induced pain. Results also indicated that pain willingness serves as a moderator in the relationship between catastrophizing and task performance during induced pain. Conclusion: The pain willingness factor of acceptance and catastrophizing both appear to be strong predictors for self-reported pain interference. During an objective assessment of pain interference, however, pain willingness shows a stronger effect and attenuates the negative impact of catastrophizing on task functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relation of pain and depression with various health-promoting behaviors in African American elders.

Purpose/Objective: In this study, the authors investigated how presence of pain interferes with various health behaviors in a sample of urban African American elders, examining depression as a potential mediator. Research Method/Design: 74 African Americans over the age of 60 years and residing in Detroit participated in both self-report questionnaires and physical performance measures. Regression analyses were used to determine the effect of pain interference on health behaviors, and partial correlations were used to determine whether depression mediated the relations. Results: The authors found that pain interference was significantly related to physical functioning and frequency of aerobic exercise. The latter relation (pain interference and frequency of exercise) was partially mediated by depression. Conclusions/Implications: Given these findings, the effect of pain interference on health behaviors is neither simple nor direct, and depression may be a key variable. Identification and treatment of pain and depression in older persons may reduce physical impairment and health care costs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chicken microchromosomes are hyperacetylated, early replicating, and gene rich

Persons with chronic pain often report a range of physical symptoms beyond their primary pain complaint itself. We predicted that non-specific physical symptom complaints would correlate more strongly with pain-related distress than with general measures of distress, and that they would contribute directly to disability. Results from 210 adults with chronic pain showed that collateral physical complaints are common in persons with chronic pain. Correlational analyses showed that greater reporting of physical complaints was associated with reports of higher pain severity, higher levels of depression, more cognitive, escape/avoidance, fearful appraisal, and physiological symptoms of pain-related anxiety and more physical and psychosocial disability. Regression analyses showed that, with pain-related anxiety variables entered either before or after depression, physiological symptoms of pain-related anxiety significantly predicted physical complaints. In comparison with cognitive and somatic depression symptoms physiological symptoms of pain-related anxiety were the stronger predictor.     

Meta-analysis of psychological interventions for chronic low back pain.

The purpose of this meta-analysis of randomized controlled trials was to evaluate the efficacy of psychological interventions for adults with noncancerous chronic low back pain (CLBP). The authors updated and expanded upon prior meta-analyses by using broad definitions of CLBP and psychological intervention, a broad data search strategy, and state-of-the-art data analysis techniques. All relevant controlled clinical trials meeting the inclusion criteria were identified primarily through a computer-aided literature search. Two independent reviewers screened abstracts and articles for inclusion criteria and extracted relevant data. Cohen's d effect sizes were calculated by using a random effects model. Outcomes included pain intensity, emotional functioning, physical functioning (pain interference or pain-specific disability, health-related quality of life), participant ratings of global improvement, health care utilization, health care provider visits, pain medications, and employment/disability compensation status. A total of 205 effect sizes from 22 studies were pooled in 34 analyses. Positive effects of psychological interventions, contrasted with various control groups, were noted for pain intensity, pain-related interference, health-related quality of life, and depression. Cognitive-behavioral and self-regulatory treatments were specifically found to be efficacious. Multidisciplinary approaches that included a psychological component, when compared with active control conditions, were also noted to have positive short-term effects on pain interference and positive long-term effects on return to work. The results demonstrated positive effects of psychological interventions for CLBP. The rigor of the methods used, as well as the results that reflect mild to moderate heterogeneity and minimal publication bias, suggest confidence in the conclusions of this review. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The prevalence of phantom limb experience in amputees.

Reviewed the records of 716 amputees who utilized Canadian prosthetic facilities to determine the prevalence of phantom limb pain or sensation and the possible influence of demographic variables on their presence. The prevalence of phantom pain (62.4%) and phantom sensation (84.1%) tended to confirm recent surveys in other nationalities. Years since amputation was the only variable found to influence the report of either pain or sensation. Ss who lost their limbs prior to 1960 reported significantly more pain (73.3%) than Ss who lost their limbs after 1976 (51.1%). There was also a slight tendency for older Ss to report phantom limb pain more often than younger Ss. Findings suggest that the incidence of phantom limb pain is declining. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A randomized trial of a representational intervention for cancer pain: Does targeting the dyad make a difference?

Objective: To determine the efficacy in overcoming attitudinal barriers to reporting cancer pain and using analgesics of an educational intervention presented to patients accompanied by a significant other (SO) as compared with patients alone. Design: Patient–SO pairs (N = 161) were randomized to the dyad condition (patient and SO received the intervention), solo condition (patient received the intervention), or care as usual. Dyad and solo conditions received the intervention at baseline (T1) and 2 and 4 weeks later. Main Outcome Measures: Patients' and SOs' attitudes about analgesic use and patients' pain outcomes (pain severity, pain relief, interference with life, negative mood, and global quality of life [QOL]) at T1, 5 weeks later (T2), and 9 weeks later (T3). Results: Completers' analyses revealed no significant differences between groups at T2. At T3, patients in the dyad and the solo groups showed greater decreases in attitudinal barriers as compared with controls. T1–T3 changes in patients' barriers mediated between the dyad and solo interventions and pain severity, pain relief, pain interference, negative mood, and global QOL. Conclusion: The intervention was no more efficacious when it was presented to dyads than to patients alone. Conditions under which SOs should be included in interventions need to be determined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Calcium and signal transduction in granulocytes

The purpose of this study was to examine the relationships among negative affect (depression, anxiety, and anger), microstressors (hassles), temporomandibular disorder (TMD) pain severity, and life interference, using structural equations modeling. One hundred four subjects were recruited from the Parker Mahan Facial Pain Clinic at the University of Florida. Significant positive direct effects were found for paths between pain severity and life interference; pain severity and negative affect; and negative affect and life interference. These results are consistent with a learning or behavioral model of suffering and suggest that negative affect is an important mediating variable in the relationship between pain and life interference. Microstressors were not a significant predictor and may not be a relevant issue in the TMD population. The results suggest that the impact of chronic pain conditions is influenced by both pain and negative affect, and assessment and treatment of chronic TMD disorders may better benefit from a multidisciplinary approach.     

Healthy youth development as a model for youth health promotion. A review

To explore the possible mechanisms of phantom limb discomfort after amputation, three amputees with phantom limb pain were studied. This study examined the change of regional cerebral blood flow using technetium-99m hexamethylpropyleneamine oxime-single photon emission computerized tomography, which was arranged at the time of severe phantom limb discomfort and after the discomfort subsided or was completely relieved. Nine representative transverse slices parallel to the orbitomeatal line were selected for quantification. The cortical ribbon (2-cm thickness) was equally subdivided into 12 symmetrical pairs of sector regions of interest in each slice. The irregularly shaped regions of interest were drawn manually around the right thalamus and basal ganglion and then mirrored to the left thalamus and basal ganglion. The contralateral to ipsilateral ratio of regional cerebral blood flow for each area was calculated. The intensity of phantom limb pain was evaluated on a 0 to 10 visual analog scale. In Cases 1 and 2, the contralateral to ipsilateral regional cerebral blood flow ratios of multiple areas of the frontal, temporal, or parietal lobes were increased at the time of more severe phantom limb pain, and the ratios were normalized or even decreased when the phantom limb pain subsided. In Case 3, increased contralateral to ipsilateral regional cerebral blood flow ratios were also found over the frontal, temporal, and parietal lobe. However, most of the increased regional cerebral blood flow ratios of regions of interest in the first study persisted in the follow-up study. Also, the regional cerebral blood flow ratios of greater number of regions of interest of the same gyrus and new gyrus were increased. There was no significant right-left difference of regional cerebral blood flow over bilateral thalami and basal ganglia in all three cases. The results suggested that phantom limb pain might be associated with cortical activation involving the frontal, temporal, or parietal cortex, and it may imply the possibility of the existence of an ascending polysynaptic pathway that conveys the uncomfortable phantom limb sensation to the cerebral cortex. These findings may also indicate that reorganization of the cortical blood flow occurs in amputees. However, it is still difficult to conclude that the changes in regional cerebral blood flow were attributable directly to pain. With no comparison group of amputees and because of the small number of cases, it is hard to generalize about cerebrocortical involvement in phantom pain, and it is possible that the findings represent a normal phenomenon seen after 'amputation. Another possibility is that the findings represent increased arousal caused by pain rather than an intrinsic pain pathway. Further study is worthwhile.